Cervical pessaries have long been proposed as a means to prevent conception. The theory is that when properly proportioned and inserted in the cervical neck, they will prevent conception by preventing passage of sperm into the uterus.
The problem presented is straightforward. The neck of the cervix is tubular, and various techniques have been proposed to close it. One is to provide an external cap. Another is to fill the lumen of the neck to prevent flow between the device and the wall. Yet another is to cap the inner end of the neck. Some devices have proposed using two or even all three of these techniques.
It is a matter of at least mild surprise that in view of the theoretically perfect reliability of such a device, and of the elegant simplicity of its design and function, it is not generally a popular choice.
It does, of course, have its limitations. For one it must be removed monthly to enable menstrual flow to occur. Thus, insertion and removal are regularly necessary, and at least the insertion does require care and skill beyond those required by some other conventional devices.
Further, some women require reassurance that the device is properly in place. In some known devices this assurance is not available.
It is an object of this invention to provide an easily inserted pessary which is reliably retained, and whose functionality can readily be ascertained by its wearer whenever she wishes to have reassurance, thereby to produce a more acceptable product.